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I think Jesse is making a good point there. I had not understood he was asking about the HalfSpeed feature. Since the EDP does it by lowering the sample rate of the D/A it may sound less clean than with interpolation at full sample rate. And its not so wrong to call this process Oversampling. I dont quite understand the thing about the older sampler though, since it needs to change the sample rate for each note you play simultaneously, so its not possible adapt the D/A convertor rate as the EDP does. Probably they use a simple interpolation in the old model. >The Echoplex and the old sampler pitch change by really changing the >sample rate on the D/A convertors. The newer sampler probably does >it digitally by interpolation techniques or other DSP pitch-shift >techniques, and maintains the same sample rate on the convertor. I >don't think oversampling or the anti-alias filtering would have >anything to do with the effect you are hearing. > >Oversampling isn't "smoothing out" the waveform. It is a >mathematical technique that spreads out the aliased frequency bands >so they aren't right next to each other. That makes it simpler to >filter out the aliased bands with a less-complex low-pass filter >with a gentler slope. > >kim > >At 02:39 AM 6/24/2004, Jesse Ray Lucas wrote: >>I was just curious since comparing the sound of an older Akai S2000 >sampler >>against the sound of a newer S5000 sampler. Although both are 16-bit >>samplers, the older model sounds "grittier" when you pitch samples down >or >>resample to a lower bandwidth. The EDP sounds gritty, too, when you >shift >>into halfspeed. >> >>As I understood that article it was saying that during the D-A conversion >>the oversampling process was the interpolation of in-between samples into >>the signal to smooth the waveform out. >> >>Just trying to figure out what makes that sound sound the way it does. >If >>you say it's the anti-aliasing filters that matter, then I believe you. >>Thanks for the info. >> >>-J >> > >______________________________________________________________________ >Kim Flint | Looper's Delight >kflint@loopers-delight.com | http://www.loopers-delight.com -- ---> http://Matthias.Grob.org